Siftproof bag



v Dec. 15, 1942. 's. w. POPPE SIFT-VPROOF BAG Filed May 1'7, 1941 FIG. 2.

FIG.

FIG. 5.

lNVENTOk 9501265 w. POPPE ATTORNEY Patented Dec. 15, 1942 UNITED *STATESPATENT OFFICE SIFTPROOF BAG George W. Poppe, Brooklyn, N. Y., assignor to Equitable Paper Bag 00. Inc., Long Island City, N. Y., a corporation of New York Application May 17, 1941, Serial No. 393,887

1 Claim. (o1. 229 55) This invention relates to a sift-proof bag, and more particularly to the closure of a multi-ply bag.

In the making of the usual satchel bottomed bag, or the so-called self-opening bag having bellows folds, a bag tube section is usually provided with a pair of parallel slits extending from the bottom edge of such a section and of a suitable length. The bottom slitted portion is then opened up to form the closure.

When bags of this character contain a number of plies, the folds which are necessary in producing the closure cause excessive bulkiness.

An object of the present invention is to produce a multi-ply bag which not only may readily be made on a bag machine by processes already well known, but one in which excessive bulkiness in the closure is reduced and a more sift-proof, stronger and better pasted bottom is attained.

In carrying out these and other objects, a feature of the present invention relates to the manner of slitting a bag tube section, whereby when the end is opened up, there will be a larger number of surfaces to which paste maybe applied in forming a closure for either the'top or the bottom of such a bag tube section, than in the usual satchel bottomed or self-opening bag.

A further feature relates to the provision of slits made at an angle instead of parallel to each other, the slits in one ply running in a different direction from the slits in another ply,

The invention will be better understood from the following detailed description and claim when taken in connection with the accompanying drawing in which:

Fig. l is a plan view of one end of a bag tube section which may constitute the outer ply of a multi-ply bag, showing the manner of slitting the outer ply.

Fig. 2 is a similar view of an inner ply showing the manner of slitting such ply.

Fig. 3 is a view similar to Figs. 1 and 2 but showing the inner ply nested within the outer ply, the slits of the inner ply being indicated in dotted lines.

Fig. 4 is a very much enlarged view of the end of a bag tube section, slit as shown in Fig. 3, but opened up to form a diamond fold and,

Fig. 5 is a view similar to Fig. 4 and on the same scale, but with one of the flaps folded down and pasted.

Referring to the drawing an outer ply of a multi-ply bag tube section is shown in Fig. 1 which section is slit at I and 2. The sides of slit 1 are indicated at 3 and 4 and the sides of slit 2 are indicated at 5 and 6. The slits I and 2 of the outer ply extend from the bottom edge of the bag tube section towards the longitudinal axis of the section.

The inner ply shown, in Fig. 2 is provided with slits 8 and 9. The edges of slit 8 are indicated at I0 and H and the edges of slit 9 are indicated by the reference character l2 and [3. The slits 8 and 9 extend from the bottom edge of the bag tube section away from the longitudinal axis of such section.

When the inner ply is nested within the outer ply, the slits appear as indicated in Fig. 3. It will then be seen that a bag tube section is produced having slits formed at its bottom edge and within its side margins which slits enable a diamond fold to be made when the bottom of the section is opened out. It will also be seen that the slits in one of the plies extend from the bottom edge towards the longitudinal axis of the bag tube section and the slits-in the other ply run from the bottom edge away from the longitudinal axis of the bag tube section. It will also be noted that the ends of the slits in the respective plies meet at a common point.

When the bag tube section is opened out in the formation of a diamond fold, the bottom closure presents the appearance shown in Fig. 4. Comparing this figure with Figs. 1, 2 and 3, it will be noted that the edge 3 of the slit l and the edge 4 of the same slit form an angle with each other which is greater than right angle. It will also be noted that the edge 5 of the slit 2 and the edge 6 of the same slit likewise form an angle with each other which is greater than a right angle.

The edges l0 and H of the slit 8 in the inner ply and the edges I2 and I3 of the slit 9 form an angle with each other which is less than a right angle.

In securing the bottom, paste may be applied to the outside of the outer flap within the area bounded by the lines A-B and 0-D. It may also be applied to the triangular portions [5, l6, l1 and i=8. In applying the paste to the portion l6, however, the paste does not extend beyond the line which is a continuation of the serrated edges 20.

It will thus be seen that by cutting the slits at an angle, portions of the plies are spread out in somewhat fan-shaped formation and a larger area of surface is provided for receiving the paste. Furthermore, by spreading out the portion of the plies in fan shaped fashion, a much stronger,

more sift-proof and more easily pasted closure is provided.

In order to complete the closure the lower flap may be folded along the score line YY Fig. 4 and such a folded condition of the closure is shown in Fig. 5. The top flap may then be folded along score line XX Fig. 5, to completely close one end of the bag section.

In the actual process of making such a closure on a bag machine it would be more usual first to close the upper flap along the score line XX and subsequently close the bottom along the score line Y-Y, although either method of procedure may be adopted depending on circumstances and convenience in a particular case.

As stated on page 1 of the specification, one

of the objects of the invention is to produce a multi-ply bag which may be made on a bag ma chine by processes already well known. The bag section of the present invention may be produced from a web such as disclosed in my Patent No. 1,798,168, March 31, 1931 and the cuts may be made by dies such as shown in Figs. 6 and 8 of said patent. Since the bag of the present in.- vention is a multi-ply bag,,two webs would be cut separately and folded together to form a bag tube from which bag sections could be produced.

It is to be noted that the angle which the slits l and 2; and 8 and 9 make with the bottom edge of a bag tube section while shown is approximate- 1y 60, such angle may be varied to vary the extent of different areas to be pasted. For instance, it may sometimes be desirable to make the slits at such an angle that the areas 16 may be a little larger and the areas I! a little smaller than shown in Fig. 4. I therefore do not desire to be limited to any exact angle at which the slits are made.

What I claim is: v

A flat multi-ply bag tube section having a pair of slits formed at its bottom edge of each panel of each ply and within its side margins to form a closure when the bottom is opened out and folded, the slits in an outer ply in each panel running from its bottom edge towards the longitudinal axis of the bag tube section and the slits in an inner ply in each panel running from its bottom edge away from the longitudinal axis of the bag. tube section, the ends of the pair of, slits in an outer ply being spaced further apart at the bottom edge of a section than the corresponding pair of slits of the inner ply at the bottom edge of said ply, with the ends of the converging slits in the two plies being coincident in the unopenedout condition of the bag tube section bottom.

GEORGE W. POPPE. 

